I don't think Cuddy was doing anything particularly out of the ordinary...from the moment House walked into Cuddy's office and gave her the line about the kid, he was stuck in his own head. She was pissed but mostly just tired and has steeled herself against his antics for so long that she just decided to leave before either of them said something they'd really regret, and that was the end of it.
His mind made an effort to hold on to what was important to him while cutting out the noise and things that interfered (Amber, Cuddy's baby taking away her attention to him), and then continued to delve inward on itself, satisfying the reasoning centers of his brain with emotional responses that made sense. He knows Cuddy cares for him and would do anything to see him cured, so took advantage of that (again, in his head), but to do so it also had to play out a reasonable scenario in which he detoxes so Cuddy would be there. After the detox, well he wouldn't reasonably have pills around, so the medicine is replaced by an errant tube of lipstick. His interactions with the other patients probably happened, but his perception of events wasn't organizing itself properly (the pancreatic solution to Scott that was subconsciously for Reiner); I don't believe they were part of his mental breakdown.
Cuddy sent Carl Reiner to House as part of her usual probing to force him into clinic duty, a normal day at the office; House is of course having none of it and continues his usual games, while also pushing the envelope continually with various stalker-like behavior trying to prove to Wilson (and ultimately, himself) that Cuddy is hot for him. Having no success he challenges her feelings directly by announcing it openly to the entire lobby, which of course is the final straw after the sleight about her kid, given that it's a blatant lie and destructive to her authority. Only once he attempts to talk to her and reconcile the matter does his rationale suddenly get a splash of cold water and realize that nothing is quite working out in his head...and at that point it all fits, and the noise is not only no longer supressed, but comes back in greater force, including new aberrations (Kutner) that have compounded on the continual loss/guilt/pain/whatever you want to call it that he suffers from.
He waves the white flag and realizes this is not something he can conquer on his own.